In general, there are various types of conveyor systems used to displace sensitive products from one position to another. Conveyor systems are frequently employed to transfer products between stations having one or more machines that perform operations on the products to convert the products from one form to another form. Many conveyor systems will typically also then transport finished products to downstream equipment for packaging, for example. In one example, a conveyor is used with a flexible sheeter that is capable of converting coated papers or other similar products from roll form to stacked cut sheets of paper. More specifically, a portion of the sheeter is referred to as a discharge conveyor belt that receives stacked sheets of product, for example, for wrapping and further packaging downstream of the discharge conveyor.
In many cases, the downstream equipment requires the stacks of product to be delivered in a consistent manner. This is usually at a predefined pitch and velocity to allow the downstream equipment to “phase” to the incoming product. More specifically, and for example, the sheeter delivers product off of the discharge conveyor in a pulse form, which may include 1 or multiple stacks back-to-back with a gap following the grouping or “pulse” of plurality of stacks until the next pulse of product is delivered. Because phasing of downstream equipment is easier when there is a consistent pitch (distance) and velocity of incoming products, there is a need to combine the aforementioned pulsed discharges and form a continuous stream that can be uniformly gapped with a speed-up conveyor placed between the sheeter and the downstream equipment.
One method of combining the pulsed discharges of products is to have a second simple conveyor between the gapping conveyor and the sheeter's discharge conveyor belt. This second conveyor receives a pulse “n” and then slows down to allow pulse “n+1” to “catch up.” Due to different velocities of the gapping conveyor, the second simple conveyor, and the sheeter's discharge conveyor, this process results in relative movement or “skidding” between the product and the conveyor that serves to eliminate the gaps between the pulses. This “skidding” can mar several of the bottom sheets of each stack of the product and, even if the impurities imparted to the sheets due to skidding are subtle, they can lead to undesirable bleeding of deposited ink during inkjet printing operations, rendering printed pages unsuitable for use. As such, skidding can result in latent defects in reams of paper, which defects only come to light once costly printing operations are performed by an end user. Processing operations that avoid relative movement between conveyor belts and stacks of sheets being transported thereon would be advantageous.